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1. User feedback: When the pump is set to 10–50% (with the pump outlet connected directly back to the tank), the liquid flowing from the pump outlet does so in intermittent bursts (since a previous pump was able to deliver a continuous flow even when the regulator was set at 10% or even 5%); as a result, the measurement is inaccurate, and a replacement pump is required. He arrived at the result by comparing products of the same brand, same model, and in the same working condition. The problem is: if the liquid cannot be discharged in a continuous flow, it indeed affects the accuracy of the flow rate. Therefore, to obtain a continuous flow in his original pipeline, a backpressure valve and a pressure regulator must be added to ensure accuracy. It is rare to occasionally find a continuous flow in his pipeline. 2. User feedback: At the high operating pressure level, there was leakage in the pump’s seal; they believed that there was a quality issue with the seal and requested that it be replaced. The problem: It has been found that there are some small particles in the liquid, which are the main cause of seal leakage. Since the metering pump is a piston-type pump with U-shaped rubber seals that cannot be compressed, the presence of hard particles in the liquid will inevitably lead to leakage from the pump. Therefore, it is recommended to install an inline filter at the pump’s inlet. 3. User feedback: Shortly after operation, the three-phase motor heats up, forcing it to stop; it must cool down before it can be restarted. The user believes there is a problem with the motor and requests confirmation for replacement. The problem: The 3-phase motor supplied by the metering pump is a dual-voltage motor with specifications of 230/400V, 3-phase, 50Hz, and IP55 protection; it can operate either at 400V, 3-phase, 50Hz (the power supply conditions in China) or at 230V, 3-phase, 50Hz (the power supply conditions in some regions outside China). In China, the wiring method is a Y-connected configuration. Apparently, the customer made an error in the wiring, which resulted in insufficient voltage being supplied to the motor. It is due to improper use; the quality of the pump body is good. Fortunately, the user discovered it in time, preventing the motor from being damaged. In this situation, a user once burned out a motor as a result. 4 User feedback: For the metering pump, it was found right from the start of use that there was a horizontal crack about 5 cm long on the upper part of the pump head’s surface; the pump would leak fluid while in operation. The user assumed there was a problem with the quality of the plastic pump head and requested a replacement. The problem is that, in order to achieve a tight seal at the outlet during installation, users over-tighten the pump outlet components, which causes these components to press tightly against the pump head and pull on it. As a result, leakage occurs after the pump is in use. To prove the correctness of this explanation, the metering pump was demonstrated on-site at the factory by using any intact pump head available in the warehouse for testing. When the outlet components were over-tightened using a screw, the pump head immediately emitted a loud noise, and obvious cracks could be seen on its surface; it is therefore clear that the issue lies in the installation process. Since an O-ring is pre-installed on the inner end face of the pump’s inlet and outlet components for end-face sealing, there is no need to worry about leaks, nor is it necessary to over-tighten the outlet components.